Heat recycling device, carbon dioxide energy storage system and control method thereof

Abstract

The present invention discloses a heat recycling device, a carbon dioxide energy storage system and a control method thereof. The heat recycling device comprises a cold storage container, a first heat storage container, a second heat storage container, a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger; the first heat exchanger and the second heat exchanger are sequentially connected to the output end of the compressor of the energy storage component, and the third heat exchanger and the fourth heat exchanger are sequentially connected to the input end of the turbine of the energy release component; the heat recycling device comprises a first heat circulation loop and a second heat circulation loop, the first heat circulation loop comprises a cold storage container, a first heat exchanger, a first heat storage container, a third heat exchanger and a fourth heat exchanger which are sequentially connected in a circulation manner, and the second heat circulation loop comprises a cold storage container, a second heat exchanger, a second heat storage container and a fourth heat exchanger which are sequentially connected in a circulation manner. The scheme of the present invention can improve the heat recycling efficiency in the carbon dioxide energy storage system and the overall efficiency of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and in particular to a heat recycling device, a carbon dioxide energy storage system and a control method thereof. Background Art

[0002] Using clean energy such as solar energy and wind energy to slow down the consumption of non-renewable traditional energy such as coal and oil has become an inevitable choice. Due to the intermittent, volatile, and peak-shifting characteristics of clean energy, energy storage technology has become one of the key technologies for the development of clean energy. At present, energy storage technology based on the gas-liquid phase change cycle of carbon dioxide uses excess electricity or clean energy to compress and condense gaseous carbon dioxide at room temperature and pressure in the gas storage unit into liquid carbon dioxide and store it in the liquid storage unit during the off-peak period of electricity consumption, and stores the heat energy generated during the compression process. During the peak period of electricity consumption, the stored heat energy is used to heat the liquid carbon dioxide to gaseous state. The gaseous carbon dioxide drives the turbine to drive the generator to generate electricity, and the gaseous carbon dioxide after work returns to the gas storage unit for recycling. It has the advantages of simple structure, flexible layout, and high energy storage efficiency, and has gradually attracted widespread attention.

[0003] In the carbon dioxide energy storage system, a heat exchange device is usually provided for recycling heat and cold energy between the energy storage component and the energy release component. Chinese patent application CN112985145A discloses an energy storage device based on the gas-liquid phase change of carbon dioxide. Referring to its attached figure, the heat exchange circuit of the heat exchange component includes a cold storage tank, an energy storage heat exchanger, a heat storage tank and an energy release heat exchanger which are connected in a circular manner. During the energy storage process, the low-temperature heat exchange medium flows from the cold storage tank to the energy storage heat exchanger for heat exchange, absorbs the heat in the compressed high-temperature carbon dioxide, and increases the temperature of the heat exchange medium. The heated high-temperature heat exchange medium flows to the heat storage tank, and the heat is temporarily stored in the heat storage tank. During the energy release process, the high-temperature heat exchange medium flows from the heat storage tank to the energy release heat exchanger for heat exchange, and transfers the heat to the carbon dioxide flowing through the energy release heat exchanger. After the heat exchange is completed, the cooled heat exchange medium flows to the cold storage tank.

[0004] The technical solution disclosed in the above patent application is as follows: during the energy storage process, the low-temperature heat exchange medium flowing out of the cold storage tank exchanges heat with the high-temperature carbon dioxide only through one heat exchanger (energy storage heat exchanger). As the temperature of the low-temperature heat exchange medium increases and the temperature of the high-temperature carbon dioxide decreases, the heat exchange efficiency between the two decreases rapidly, and the temperature of the high-temperature carbon dioxide cannot be further reduced, and the heat energy cannot be fully recovered, which reduces the overall efficiency of the energy storage system; during the energy release process, the high-temperature heat exchange medium flowing out of the heat storage tank exchanges heat with the low-temperature carbon dioxide only through one heat exchanger (energy release heat exchanger). As the temperature of the high-temperature heat exchange medium decreases, the heat exchange efficiency between the two decreases rapidly, and the temperature of the high-temperature carbon dioxide cannot be further reduced. As the temperature of the low-temperature carbon dioxide increases, the heat exchange efficiency between the two decreases rapidly, and the temperature of the low-temperature carbon dioxide cannot be further increased, and the thermal energy cannot be fully utilized, thereby reducing the overall efficiency of the energy storage system; moreover, in the energy release process, since the thermal energy cannot be fully utilized, the temperature of the high-temperature heat exchange medium is still higher than the temperature range required by the cold storage tank after heat exchange and cooling in the energy release heat exchanger. Therefore, a heat exchange medium cooler needs to be added to the energy release heat exchanger and the cold storage tank. The high-temperature heat exchange medium after heat exchange is cooled again by the heat exchange medium cooler to make its temperature meet the requirements of the cold storage tank, thereby increasing the cost of the system. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a heat recycling device, a carbon dioxide energy storage system and a control method thereof to solve the problem of how to improve the heat recycling efficiency and the overall efficiency in the carbon dioxide energy storage system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a heat recycling device, which is applied to a carbon dioxide energy storage system. The carbon dioxide energy storage system includes an energy storage component and an energy release component. The heat recycling device includes a cold storage container, a first heat storage container, a second heat storage container, a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger; the first heat exchanger and the second heat exchanger are connected in series with each other and the input end of the first heat exchanger is connected to the output end of the compressor of the energy storage component, the third heat exchanger and the fourth heat exchanger are connected in series with each other and the output end of the third heat exchanger is connected to the input end of the turbine of the energy release component;

[0008] The heat circulation device comprises a first heat circulation loop and a second heat circulation loop, wherein the first heat circulation loop comprises the cold storage container, the first heat exchanger, the first heat storage container, the third heat exchanger and the fourth heat exchanger which are connected in a circular manner in sequence, and the second heat circulation loop comprises the cold storage container, the second heat exchanger, the second heat storage container and the fourth heat exchanger which are connected in a circular manner in sequence;

[0009] In the energy storage stage, the temperature stored in the cold storage container is T 11 The heat exchange medium is respectively input into the first heat exchanger and the second heat exchanger; in the first heat exchanger, the temperature is T 11 The temperature of the heat exchange medium output from the compressor is T 21 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 12 The heat exchange medium is input into the first heat storage container for storage and obtains a temperature of T 22 The carbon dioxide working medium is input into the second heat exchanger; in the second heat exchanger, the temperature is T 11 The heat exchange medium has a temperature of T 22 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 13 The heat exchange medium is input into the second heat storage container for storage and obtains a temperature of T 23 The output of carbon dioxide as working fluid;

[0010] In the energy release stage, the temperature stored in the first heat storage container is T 12 The heat exchange medium is input into the third heat exchanger, and the temperature stored in the second heat storage container is T 13 The heat exchange medium is input into the fourth heat exchanger; in the third heat exchanger, the temperature is T 12 The temperature of the heat exchange medium output from the fourth heat exchanger is T 25 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 14 The heat exchange medium is input into the fourth heat exchanger and obtains a temperature of T 26 The carbon dioxide working fluid is input into the turbine; in the fourth heat exchanger, the temperature is T 13 The heat exchange medium and the temperature are T 14 The heat exchange medium is combined and the temperature of the input to the fourth heat exchanger is T 24 The liquid carbon dioxide working medium is heated and evaporated to obtain the temperature T 11 The heat exchange medium is input into the cold storage container for storage and the temperature is T 25 The carbon dioxide working medium is input into the third heat exchanger;

[0011] Among them, T 11 <T 13 <T 14 <T 12 , T 24 <T 25 <T 26 , T 23 <T 22 <T 21 , and T11 <T 21 , T 24 <T 13 , T 25 <T 12 .

[0012] In a specific embodiment, 20°C ≤ T 11 ≤30℃, 230℃≤T 12 ≤280℃, 40℃≤T 13 ≤60℃, 60℃≤T 14 ≤80℃; 220℃≤T 21 ≤310℃, 90℃≤T 22 ≤110℃, 55℃≤T 23 ≤85℃, 20℃≤T 24 ≤28℃,T 25 =31℃, 230℃≤T 26 ≤280℃.

[0013] In a specific embodiment, the heat measurement inlet of the first heat exchanger is connected to the output end of the compressor, the heat measurement outlet of the first heat exchanger is connected to the heat measurement inlet of the second heat exchanger, and the temperature is T 23 The carbon dioxide working medium is output from the heat outlet of the second heat exchanger;

[0014] The cold side inlet of the first heat exchanger is connected to the outlet of the cold storage container through a first pipeline, the cold side outlet of the first heat exchanger is connected to the inlet of the first heat storage container through a second pipeline, the cold side inlet of the second heat exchanger is connected to the outlet of the cold storage container through a third pipeline, and the cold side outlet of the second heat exchanger is connected to the inlet of the second heat storage container through a fourth pipeline;

[0015] The cold outlet of the third heat exchanger is connected to the input end of the turbine, the cold inlet of the third heat exchanger is connected to the cold outlet of the fourth heat exchanger, and the temperature is T 24 The liquid carbon dioxide working medium is input from the cold side inlet of the fourth heat exchanger;

[0016] The heat measuring inlet of the third heat exchanger is connected to the outlet of the first heat storage container through a fifth pipeline, the heat measuring outlet of the third heat exchanger is connected to the heat measuring inlet of the fourth heat exchanger through a sixth pipeline, the heat measuring inlet of the fourth heat exchanger is also connected to the outlet of the second heat storage container through a seventh pipeline, and the heat measuring outlet of the fourth heat exchanger is connected to the inlet of the cold storage container through an eighth pipeline;

[0017] Wherein, at least the first pipeline, the third pipeline, the fifth pipeline and the seventh pipeline are respectively connected with a flow control valve.

[0018] In a specific embodiment, the fourth heat exchanger is further connected to an external heat source via a circulation pipeline, and the circulation pipeline is connected to the fourth heat exchanger at a position adjacent to a cold side outlet of the fourth heat exchanger.

[0019] In a specific solution, the heat exchange medium is heat transfer oil or water.

[0020] The second aspect of the present invention is to provide a carbon dioxide energy storage system, comprising a gas storage unit, an energy storage component, a liquid storage unit and an energy release component connected in a closed loop in sequence, wherein the carbon dioxide energy storage system also includes the heat recycling device as described above.

[0021] In a specific embodiment, the energy storage component includes a low-pressure compressor and a high-pressure compressor, the first heat exchanger and the second heat exchanger are connected in series between the low-pressure compressor and the high-pressure compressor, the first heat exchanger is connected to the output end of the low-pressure compressor, the second heat exchanger is connected to the input end of the high-pressure compressor, and the input end of the low-pressure compressor is connected to the air storage unit.

[0022] In a specific solution, the energy storage assembly further includes a condenser, and the output end of the high-pressure compressor is connected to the liquid storage unit through the condenser.

[0023] In a specific embodiment, the liquid storage unit is connected to the fourth heat exchanger via a liquid pump, and the liquid pump transfers the liquid in the liquid storage unit to a liquid having a temperature of T 24 The liquid carbon dioxide working medium is input into the fourth heat exchanger; the output end of the turbine is connected to the gas storage unit.

[0024] The third aspect of the present invention is to provide a control method for the carbon dioxide energy storage system as described above, wherein the control method includes an energy storage stage and an energy release stage; wherein:

[0025] During the energy storage phase:

[0026] The gaseous carbon dioxide working medium in the gas storage unit is input into the compressor, and is compressed by the compressor to form the working medium at a temperature of T 21 The carbon dioxide working fluid is input into the first heat exchanger;

[0027] Control the cold storage container to set the temperature to T 11 The heat exchange medium is input into the first heat exchanger, and the temperature is T 21 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 12 The heat exchange medium is input into the first heat storage container for storage and the temperature is obtained as T 22The carbon dioxide working medium is input into the second heat exchanger;

[0028] Control the cold storage container to set the temperature to T 11 The heat exchange medium is input into the second heat exchanger, and the temperature is T 22 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 13 The heat exchange medium is input into the second heat storage container for storage and the temperature is obtained as T 23 The output of carbon dioxide as working fluid;

[0029] For the temperature T 23 The carbon dioxide working fluid is condensed and liquefied to obtain the temperature T 24 The liquid carbon dioxide working medium is input into the liquid storage unit;

[0030] During the energy release phase:

[0031] The temperature in the liquid storage unit is T 24 The liquid carbon dioxide working medium is input into the fourth heat exchanger;

[0032] Control the second heat storage container to set the temperature to T 13 The heat exchange medium is input into the fourth heat exchanger, and the temperature is T 24 The liquid carbon dioxide working medium is heated and evaporated to obtain the temperature T 11 The heat exchange medium is input into the cold storage container for storage and the temperature is T 25 The carbon dioxide working medium is input into the third heat exchanger;

[0033] Control the first heat storage container to set the temperature to T 12 The heat exchange medium is input into the third heat exchanger, and the temperature is T 25 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 14 The heat exchange medium is input into the fourth heat exchanger and the temperature is T 26 The carbon dioxide working medium is input into the turbine;

[0034] Wherein, the temperature is T 14 The temperature of the heat exchange medium output from the second heat storage container is T 13 After the heat exchange medium is combined, the temperature T 24 The liquid carbon dioxide working medium is heated and evaporated to form the temperature T 11 The heat exchange medium is input into the cold storage container for storage; the temperature is T 26 The carbon dioxide working medium is input into the gas storage unit after the temperature is reduced by the turbine doing work.

[0035] The heat recycling device, carbon dioxide energy storage system and control method thereof provided by the embodiments of the present invention have the following beneficial effects compared with the prior art:

[0036] The output end of the compressor of the energy storage component is connected to the first heat exchanger and the second heat exchanger connected in series, and the input end of the turbine of the energy release component is connected to the third heat exchanger and the fourth heat exchanger connected in series.

[0037] In the energy storage stage, the temperature of the compressor output is T 21 The carbon dioxide working fluid is first input into the first heat exchanger, where it is heated by the temperature T input from the cold storage container. 11 The heat exchange medium undergoes the first heat exchange and is cooled to a temperature of T 22 The carbon dioxide working fluid is input into the second heat exchanger, and in the second heat exchanger, it is heated to a temperature of T 11 The heat exchange medium is used for the second heat exchange. Both heat exchanges are performed with a heat exchange medium at a lower temperature, thereby improving the heat exchange efficiency, reducing the temperature of the high-temperature and high-pressure carbon dioxide working fluid output by the compressor as much as possible, and allowing the heat energy to be fully recovered.

[0038] Furthermore, the relatively high temperature obtained by heat exchange in the first heat exchanger is T 12 The heat exchange medium is stored in the first heat storage container, and the relatively low temperature obtained by heat exchange in the second heat exchanger is T 13 The heat exchange medium is stored in the second heat storage container, and high-temperature heat exchange mediums of different temperatures are stored separately. Therefore, in the energy release stage, the relatively low temperature T is first used. 13 The heat exchange medium with a temperature of T 24 The liquid carbon dioxide working fluid is heated and evaporated to obtain a temperature of T 25 The working medium is carbon dioxide, and then the temperature is relatively high at T 12 The heat exchange medium with a temperature of T 25 The carbon dioxide working fluid is reheated, and the high-temperature heat exchange medium of different temperatures is used for heat exchange in different regions, thereby improving the heat exchange efficiency and increasing the temperature of the carbon dioxide working fluid input to the turbine as much as possible. In addition, the relatively high temperature is T 12 After the heat exchange medium undergoes the first heat exchange and cooling in the third heat exchanger, the temperature formed is T 14 The heat exchange medium is input into the fourth heat exchanger for a second heat exchange and cooling again, which can not only further utilize the heat, but also reduce its temperature to the storage requirement of the cold storage container, without the need to set up a heat exchange medium cooler, thereby reducing costs.

[0039] In summary, the solution of the present application can improve the heat recycling efficiency of the carbon dioxide energy storage system and the overall efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a structural schematic diagram of a carbon dioxide energy storage system in an embodiment of the present invention;

[0041] Figure 2 It is a schematic diagram of the structure of the heat recycling device in the embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the present invention shown in the accompanying drawings and described according to the accompanying drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0043] It should be noted that the same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0044] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0045] See also Figure 1 and Figure 2 The embodiment of the present invention first provides a heat recycling device 50 and a carbon dioxide energy storage system 100 including the heat recycling device 50 .

[0046] Specifically, Figure 1As shown, the carbon dioxide energy storage system 100 mainly includes a gas storage unit 10, an energy storage component 20, a liquid storage unit 30 and an energy release component 40 which are connected in a closed loop in sequence. Among them, the gas storage unit 10 is used to store gaseous carbon dioxide at normal pressure, and the liquid storage unit 30 is used to store liquid carbon dioxide. The gaseous carbon dioxide flowing out of the gas storage unit 10 is converted into liquid carbon dioxide with a preset energy storage pressure through the energy storage component 20, and flows into the liquid storage unit 30, and energy storage is completed in this process. The liquid carbon dioxide output from the liquid storage unit 30 is converted into gaseous carbon dioxide at normal pressure by releasing energy through the energy release component 40, and flows into the gas storage unit 10, and energy release and application are completed in this process. Usually, the energy storage component 20 compresses and liquefies the gaseous carbon dioxide into liquid carbon dioxide during the off-peak period of electricity consumption or by utilizing wind and solar power abandonment, and stores it in the liquid storage unit 30, converting the energy into compression energy and heat energy storage; during the peak period of electricity consumption, the energy release component 40 gasifies and expands the liquid carbon dioxide to do work, and releases the stored energy and converts it into electrical energy for use.

[0047] Among them, the specific composition structures of the gas storage unit 10, the energy storage assembly 20, the liquid storage unit 30 and the energy release assembly 40 can be realized by referring to existing technologies, such as the technical solutions disclosed in existing patent documents CN116221616A, CN117628836A, and CN116857027A.

[0048] As a specific example, in this embodiment, Figure 1 As shown, the energy storage component 20 mainly includes a low-pressure compressor 21, a high-pressure compressor 22 and a condenser 23 connected between the gas storage unit 10 and the liquid storage unit 30. The gaseous carbon dioxide in the gas storage unit 10 is compressed by the low-pressure compressor 21 and the high-pressure compressor 22 in turn, and then liquefied by the condenser 23 to form liquid carbon dioxide and stored in the liquid storage unit 30.

[0049] As a specific example, in this embodiment, Figure 1 As shown, the energy release component 40 mainly includes a turbine 41 connected between the liquid storage unit 30 and the gas storage unit 10. The liquid carbon dioxide in the liquid storage unit 30 is pressurized by the liquid pump 60 and input into the energy release component 40, and after being heated and evaporated and further heated to increase the temperature, it is input into the turbine 41 to perform work (such as power generation) to release energy, and is converted into gaseous carbon dioxide at normal pressure and stored in the gas storage unit 10.

[0050] Among them, the energy storage component 20 will generate a lot of heat in the process of compressing carbon dioxide gas, and the energy release component 40 needs to heat and evaporate the liquid carbon dioxide and gasify and expand it. Therefore, the existing carbon dioxide energy storage system is usually equipped with a heat exchange device, which stores heat energy in the energy storage stage, and uses the stored heat energy to heat the liquid carbon dioxide to form high-temperature and high-pressure gaseous carbon dioxide in the energy release stage, thereby driving the turbine to do external work. In this process, how to improve the heat recycling efficiency in the carbon dioxide energy storage system and thus improve the overall efficiency of the energy storage system is a problem that needs to be solved.

[0051] In order to improve the heat recycling efficiency in the carbon dioxide energy storage system, the embodiment of the present invention provides a heat recycling device 50, which is mainly used in the carbon dioxide energy storage system 100, that is, Figure 1 and 2 The carbon dioxide energy storage system 100 provided in the above embodiment of the present invention further includes a heat recycling device 50 .

[0052] Specifically, Figure 1 and Figure 2 As shown, the heat recycling device 50 provided in this embodiment mainly includes a cold storage container 51, a first heat storage container 52, a second heat storage container 53, a first heat exchanger 54, a second heat exchanger 55, a third heat exchanger 56 and a fourth heat exchanger 57.

[0053] The first heat exchanger 54 and the second heat exchanger 55 are arranged in the energy storage assembly 20, the first heat exchanger 54 and the second heat exchanger 55 are connected in series with each other, and the input end of the first heat exchanger 54 is connected to the output end of the compressor of the energy storage assembly 20. As described above, in this embodiment, as a specific case, the energy storage assembly 20 includes a low-pressure compressor 21, a high-pressure compressor 22 and a condenser 23 connected between the gas storage unit 10 and the liquid storage unit 30, as shown in FIG. Figure 1 and Figure 2The first heat exchanger 54 and the second heat exchanger 55 are connected in series with each other and connected between the low-pressure compressor 21 and the high-pressure compressor 22. The first heat exchanger 54 is connected to the output end of the low-pressure compressor 21, and the second heat exchanger 55 is connected to the input end of the high-pressure compressor 22. The input end of the low-pressure compressor 21 is connected to the gas storage unit 10, and the output end of the high-pressure compressor 22 is connected to the liquid storage unit 30 through the condenser 23. After being compressed by the low-pressure compressor 21, the gaseous carbon dioxide in the gas storage unit 10 is successively cooled by the first heat exchanger 54 and the second heat exchanger 55 for heat exchange and then input into the high-pressure compressor 22. After being compressed again by the high-pressure compressor 22, it is liquefied by the condenser 23 to form liquid carbon dioxide and stored in the liquid storage unit 30.

[0054] The third heat exchanger 56 and the fourth heat exchanger 57 are disposed in the energy release component 40, the third heat exchanger 56 and the fourth heat exchanger 57 are connected in series with each other, and the output end of the third heat exchanger 56 is connected to the input end of the turbine 41 of the energy release component 40. Specifically, Figure 1 and Figure 2 The input end of the fourth heat exchanger 57 is connected to the liquid storage unit 30 through the liquid pump 60, and the output end of the turbine 41 is connected to the gas storage unit 10. The fourth heat exchanger 57 can be understood as an evaporator, and the third heat exchanger 56 can be understood as a superheater. The liquid carbon dioxide in the liquid storage unit 30 is pressurized by the liquid pump 60 and input to the fourth heat exchanger 57 for evaporation and gasification, and then further heated by the third heat exchanger 56 to increase the temperature, and then input to the turbine 41 to do work (such as power generation) to release energy, and then converted into gaseous carbon dioxide at normal pressure and stored in the gas storage unit 10.

[0055] In this embodiment, the heat circulation device 50 includes a first heat circulation loop and a second heat circulation loop. The first heat circulation loop includes the cold storage container 51, the first heat exchanger 54, the first heat storage container 52, the third heat exchanger 56 and the fourth heat exchanger 57 which are sequentially connected in a circulation through a pipeline. The second heat circulation loop includes the cold storage container 51, the second heat exchanger 55, the second heat storage container 53 and the fourth heat exchanger 57 which are sequentially connected in a circulation through a pipeline.

[0056] In specific plans, such as Figure 1 and Figure 2As shown, the heat-side inlet of the first heat exchanger 54 is connected to the output end of the low-pressure compressor 21, the heat-side outlet of the first heat exchanger 54 is connected to the heat-side inlet of the second heat exchanger 55, and the heat-side outlet of the second heat exchanger 55 is connected to the input end of the high-pressure compressor 22. The cold-side inlet of the first heat exchanger 54 is connected to the outlet of the cold storage container 51 through a first pipeline 61, the cold-side outlet of the first heat exchanger 54 is connected to the inlet of the first heat storage container 52 through a second pipeline 62, the cold-side inlet of the second heat exchanger 55 is connected to the outlet of the cold storage container 51 through a third pipeline 63, and the cold-side outlet of the second heat exchanger 55 is connected to the inlet of the second heat storage container 53 through a fourth pipeline 64.

[0057] The cold side outlet of the third heat exchanger 56 is connected to the input end of the turbine 41, and the cold side inlet of the third heat exchanger 56 is connected to the cold side outlet of the fourth heat exchanger 57. The cold side inlet of the fourth heat exchanger 57 is connected to the liquid storage unit 30 through the liquid pump 60. The hot side inlet of the third heat exchanger 56 is connected to the outlet of the first heat storage container 52 through the fifth pipeline 65, the hot side outlet of the third heat exchanger 56 is connected to the hot side inlet of the fourth heat exchanger 57 through the sixth pipeline 66, the hot side inlet of the fourth heat exchanger 57 is also connected to the outlet of the second heat storage container 53 through the seventh pipeline 67, and the hot side outlet of the fourth heat exchanger 57 is connected to the inlet of the cold storage container 51 through the eighth pipeline 68.

[0058] The heat recycling device 50 described above, in the energy storage stage: the temperature stored in the cold storage container 51 is T 11 The heat exchange medium is respectively input into the first heat exchanger 54 and the second heat exchanger 55. In the first heat exchanger 54, the temperature is T 11 The temperature of the heat exchange medium output from the low-pressure compressor 21 is T 21 The temperature of the heat exchange medium increases and the temperature of the carbon dioxide working medium decreases, and a temperature of T is obtained at the cold side outlet of the first heat exchanger 54. 12 The heat exchange medium is input into the first heat storage container 52 for storage, and the temperature T is obtained at the heat outlet of the first heat exchanger 54. 22 The carbon dioxide working medium is input to the second heat exchanger 55. In the second heat exchanger 55, the temperature is T 11 The heat exchange medium has a temperature of T 22 The temperature of the heat exchange medium increases and the temperature of the carbon dioxide working medium further decreases, and a temperature of T is obtained at the cold side outlet of the second heat exchanger 55. 13The heat exchange medium is input into the second heat storage container 53 for storage, and the temperature T is obtained at the heat outlet of the second heat exchanger 55. 23 The carbon dioxide working fluid is output to the high-pressure compressor 22. The temperature is T 23 The carbon dioxide working medium is compressed again by the high-pressure compressor 22 and liquefied by the condenser 23 to form a temperature T 24 The liquid carbon dioxide is stored in the liquid storage unit 30 .

[0059] The heat recycling device 50 described above, in the energy release stage: the temperature stored in the first heat storage container 52 is T 12 The heat exchange medium is input to the third heat exchanger 56, and the temperature stored in the second heat storage container 53 is T 13 The heat exchange medium is input to the fourth heat exchanger 57. In the third heat exchanger 56, the temperature is T 12 The temperature of the heat exchange medium output from the fourth heat exchanger 57 is T 25 The carbon dioxide working fluid is heat exchanged, and the temperature T is obtained at the heat measurement outlet of the third heat exchanger 56. 14 The heat exchange medium is input into the fourth heat exchanger 57, and the temperature T is obtained at the cold outlet of the third heat exchanger 56. 26 The carbon dioxide working medium is input into the turbine to perform external work. In the fourth heat exchanger 57, the temperature is T 13 The heat exchange medium and the temperature are T 14 The heat exchange medium is combined and the temperature of the input to the fourth heat exchanger 57 is T 24 The liquid carbon dioxide working medium is heated and evaporated, and the temperature T is obtained at the heat measurement outlet of the fourth heat exchanger 57. 11 The heat exchange medium is input into the cold storage container 51 for storage, and the temperature T is obtained at the cold outlet of the fourth heat exchanger 57. 25 The carbon dioxide working medium is input into the third heat exchanger 56.

[0060] The heat exchange medium may be thermal oil or water, and thermal oil is preferably used.

[0061] Among them, T 11 <T 13 <T 14 <T 12 , T 24 <T 25 <T 26 , T 23 <T 22 <T 21 , and T 11 <T 21 , T24 <T 13 , T 25 <T 12 .

[0062] Therefore, in the heat recycling device 50 as described above, in the energy storage stage, the temperature output by the low-pressure compressor 21 is T 21 The carbon dioxide working medium with a temperature of T is first input into the first heat exchanger 54, and in the first heat exchanger 54, it is combined with the carbon dioxide working medium with a temperature of T input from the cold storage container 51. 11 The heat exchange medium undergoes the first heat exchange and is cooled to a temperature of T 22 The carbon dioxide working medium with a temperature of T is input to the second heat exchanger 55, and in the second heat exchanger 55, it is combined with the carbon dioxide working medium with a temperature of T input from the cold storage container 51. 11 The heat exchange medium is used for the second heat exchange, and both heat exchanges are performed with a heat exchange medium at a lower temperature, thereby improving the heat exchange efficiency, reducing the temperature of the high-temperature and high-pressure carbon dioxide working fluid output by the low-pressure compressor 21 as much as possible, and allowing the heat energy to be fully recovered.

[0063] Furthermore, the relatively high temperature obtained by heat exchange in the first heat exchanger 54 is T 12 The heat exchange medium is stored in the first heat storage container 52, and the temperature obtained by heat exchange in the second heat exchanger 55 is relatively low, which is T 13 The heat exchange medium of T is stored in the second heat storage container 53, that is, high-temperature heat exchange mediums of different temperatures are stored separately. Therefore, in the energy release stage, the relatively low temperature T is first used. 13 The heat exchange medium with a temperature of T in the fourth heat exchanger 57 24 The liquid carbon dioxide working fluid is heated and evaporated to obtain a temperature of T 25 The working medium is carbon dioxide, and then the temperature is relatively high at T 12 The heat exchange medium with a temperature of T in the third heat exchanger 56 25 The carbon dioxide working medium is heated again, and high-temperature heat exchange media of different temperatures are stored separately and used for heat exchange in different regions, thereby improving the heat exchange efficiency and increasing the temperature of the carbon dioxide working medium input to the turbine 41 as much as possible. In addition, the relatively high temperature is T 12 After the heat exchange medium is cooled for the first time in the third heat exchanger 56, the temperature formed is T 14 The heat exchange medium is input into the fourth heat exchanger 57 for a second heat exchange and cooling again, which can not only further utilize the heat, but also reduce its temperature to the storage requirement of the cold storage container 51, without the need to set up a heat exchange medium cooler, thereby reducing costs.

[0064] Therefore, the heat recycling device 50 and its corresponding carbon dioxide energy storage system 100 provided in the above embodiment can improve the heat recycling efficiency of the system and the overall efficiency of the system.

[0065] In a specific solution, by monitoring and controlling the temperature T of the heat exchange medium and the carbon dioxide working fluid at each node 11 , T 12 , T 13 and T 14 and T 21 , T 22 , T 23 , T 24 , T 25 and T 26 When the specific temperature parameters are within the following range: 20℃≤T 11 ≤30℃, 230℃≤T 12 ≤280℃, 40℃≤T 13 ≤60℃, 60℃≤T 14 ≤80℃; 220℃≤T 21 ≤310℃, 90℃≤T 22 ≤110℃, 55℃≤T 23 ≤85℃, 20℃≤T 24 ≤28℃,T 25 =31℃, 230℃≤T 26 ≤280℃, which can further optimize the heat exchange efficiency of the heat circulation loop and further improve the overall efficiency of the system.

[0066] In some preferred embodiments, specific control parameters of the temperature of the heat exchange medium and the carbon dioxide working fluid at each node are shown in Table 1 below.

[0067] Table 1: Temperature control parameters of heat transfer medium and carbon dioxide working fluid at each node (℃)

[0068]

[0069] In a preferred embodiment, at least the first pipeline 61, the third pipeline 63, the fifth pipeline 65 and the seventh pipeline 67 are respectively connected to a flow control valve 70, which controls the flow of the heat exchange medium input to the corresponding heat exchanger in these pipelines, thereby controlling the temperature of the heat exchange medium and the carbon dioxide working fluid obtained by the corresponding heat exchanger after heat exchange, so that the temperature of the heat exchange medium and the carbon dioxide working fluid at each node can fall within a preset temperature range, thereby optimizing the heat exchange efficiency of the heat circulation loop.

[0070] In a further embodiment, Figure 1 and Figure 2As shown, the fourth heat exchanger 57 is also connected to an external heat source (not shown in the figure) through a circulation pipeline 80. The circulation pipeline 80 is connected to the fourth heat exchanger 57 at a position adjacent to the cold test outlet of the fourth heat exchanger 57. Thus, the external heat source enters the rear part of the fourth heat exchanger 57 to continue heating and evaporating the liquid carbon dioxide and the evaporated carbon dioxide gas, thereby improving the heat exchange efficiency and increasing the superheat of the carbon dioxide gas.

[0071] Based on the heat recycling device 50 and its corresponding carbon dioxide energy storage system 100 provided in the above embodiment, the embodiment of the present invention also provides a control method of the carbon dioxide energy storage system 100. The control method includes an energy storage stage and an energy release stage, which are as follows:

[0072] 1. In the energy storage stage:

[0073] The gaseous carbon dioxide working medium in the gas storage unit 10 is input into the compressor, and is compressed by the compressor to form the working medium with a temperature of T 21 The carbon dioxide working medium is input to the first heat exchanger 54. In this embodiment, the gaseous carbon dioxide working medium in the gas storage unit 10 is input to the low-pressure compressor 21, and is compressed by the low-pressure compressor 21 to form the carbon dioxide working medium with a temperature of T 21 The carbon dioxide working medium is input into the first heat exchanger 54.

[0074] Control the cold storage container 51 to set the temperature to T 11 The heat exchange medium is input into the first heat exchanger 54, and the temperature is T 21 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 12 The heat exchange medium is input into the first heat storage container 52 for storage, and the temperature is obtained as T 22 The carbon dioxide working medium is input into the second heat exchanger 55.

[0075] Control the cold storage container 51 to set the temperature to T 11 The heat exchange medium is input into the second heat exchanger 55, and the temperature is T 22 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 13 The heat exchange medium is input into the second heat storage container 53 for storage, and the temperature is T 23 The output of carbon dioxide working fluid.

[0076] For the temperature T 23 The carbon dioxide working fluid is condensed and liquefied to obtain the temperature T 24 The liquid carbon dioxide working medium with a temperature of T is input into the liquid storage unit 30. In this embodiment, the second heat exchanger 5523 The carbon dioxide working fluid is output to the high-pressure compressor 22, and the temperature is T 23 The carbon dioxide working medium is compressed again by the high-pressure compressor 22 and liquefied by the condenser 23 to form a temperature T 24 The liquid carbon dioxide is stored in the liquid storage unit 30 .

[0077] 2. In the energy release stage:

[0078] The temperature in the liquid storage unit 30 is T 24 The liquid carbon dioxide working medium is input to the fourth heat exchanger 57. Specifically, the liquid carbon dioxide in the liquid storage unit 30 is input to the fourth heat exchanger 57 after being pressurized by the liquid pump 60.

[0079] Control the second heat storage container 53 to set the temperature to T 13 The heat exchange medium is input to the fourth heat exchanger 57, and the temperature is T 24 The liquid carbon dioxide working medium is heated and evaporated to obtain the temperature T 11 The heat exchange medium is input into the cold storage container 51 for storage, and the temperature is T 25 The carbon dioxide working medium is input into the third heat exchanger 56.

[0080] Control the first heat storage container 52 to set the temperature to T 12 The heat exchange medium is input into the third heat exchanger 56 and the temperature is T 25 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 14 The heat exchange medium is input into the fourth heat exchanger 57, and the temperature is T 26 The carbon dioxide working medium is input into the turbine 41.

[0081] Wherein, the temperature is T 14 The heat exchange medium with the temperature T output from the second heat storage container 53 13 After the heat exchange mediums are combined, the temperature T 24 The liquid carbon dioxide working medium is heated and evaporated to form the temperature T 11 The heat exchange medium is input into the cold storage container 51 for storage. The temperature is T 26 The carbon dioxide working medium is input into the gas storage unit 10 after the temperature is reduced by the work performed by the turbine 41 .

[0082] As described in the control method of the above embodiment, in the energy storage stage, the first heat exchanger 54 and the second heat exchanger 55 connected in series are used to heat exchange and cool down the high-temperature and high-pressure carbon dioxide working medium output by the compressor in turn. Both heat exchanges are performed with a heat exchange medium at a lower temperature, thereby improving the heat exchange efficiency, reducing the temperature of the high-temperature and high-pressure carbon dioxide working medium output by the compressor as much as possible, and allowing the heat energy to be fully recovered, and the high-temperature heat exchange mediums of different temperatures obtained after the two heat exchanges are stored separately. In the energy release stage, a relatively low-temperature heat exchange medium is first used to heat and evaporate the liquid carbon dioxide working medium in the fourth heat exchanger 57, and then a relatively high-temperature heat exchange medium is used to heat the evaporated carbon dioxide working medium again in the third heat exchanger 56. The high-temperature heat exchange mediums of different temperatures are used for heat exchange in different regions, thereby improving the heat exchange efficiency and increasing the temperature of the carbon dioxide working medium input to the turbine 41 as much as possible. Furthermore, after the relatively high temperature heat exchange medium undergoes the first heat exchange and cooling in the third heat exchanger 56, it is input into the fourth heat exchanger 57 for the second heat exchange and cooling again. This not only can further utilize the heat, but also can reduce its temperature to the storage requirement of the cold storage container 51. There is no need to set up a heat exchange medium cooler separately, thus reducing costs.

[0083] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A heat recycling device, applied to a carbon dioxide energy storage system, wherein the carbon dioxide energy storage system comprises an energy storage component and an energy release component, characterized in that: The heat recycling device comprises a cold storage container, a first heat storage container, a second heat storage container, a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger; the first heat exchanger and the second heat exchanger are connected in series with each other and the input end of the first heat exchanger is connected to the output end of the compressor of the energy storage component, the third heat exchanger and the fourth heat exchanger are connected in series with each other and the output end of the third heat exchanger is connected to the input end of the turbine of the energy release component; The heat circulation device comprises a first heat circulation loop and a second heat circulation loop, wherein the first heat circulation loop comprises the cold storage container, the first heat exchanger, the first heat storage container, the third heat exchanger and the fourth heat exchanger which are connected in a circular manner in sequence, and the second heat circulation loop comprises the cold storage container, the second heat exchanger, the second heat storage container and the fourth heat exchanger which are connected in a circular manner in sequence; In the energy storage stage, the temperature of the cold storage container is T 11 The heat exchange medium is input into the first heat exchanger and the second heat exchanger respectively; in the first heat exchanger, the temperature is T 11 The temperature of the heat exchange medium output from the compressor is T 21 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 12 The heat exchange medium is input into the first heat storage container for storage and obtains a temperature of T 22 The carbon dioxide working medium is input into the second heat exchanger; in the second heat exchanger, the temperature is T 11 The heat exchange medium has a temperature of T 22 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 13 The heat exchange medium is input into the second heat storage container for storage and obtains a temperature of T 23 The output of carbon dioxide as working fluid; In the energy release stage, the temperature stored in the first heat storage container is T 12 The heat exchange medium is input into the third heat exchanger, and the temperature stored in the second heat storage container is T 13 The heat exchange medium is input into the fourth heat exchanger; in the third heat exchanger, the temperature is T 12 The temperature of the heat exchange medium output from the fourth heat exchanger is T 25 The carbon dioxide working fluid is used for heat exchange to obtain a temperature of T 14 The heat exchange medium is input into the fourth heat exchanger and obtains a temperature of T 26 The carbon dioxide working fluid is input into the turbine; in the fourth heat exchanger, the temperature is T 13 The heat exchange medium and the temperature are T 14 The heat exchange medium is combined and the temperature of the input to the fourth heat exchanger is T 24 The liquid carbon dioxide working medium is heated and evaporated to obtain the temperature T 11 The heat exchange medium is input into the cold storage container for storage and the temperature is T 25 The carbon dioxide working medium is input into the third heat exchanger; Among them, T 11 <T 13 <T 14 <T 12 ,T 24 <T 25 <T 26 ,T 23 <T 22 <T 21 ,and T 11 <T 21 ,T 24 <T 13 ,T 25 <T 12 。 2. The heat recycling device according to claim 1, characterized in that: 20℃≤T 11 ≤30℃,230℃≤T 12 ≤280℃,40℃≤T 13 ≤60℃,60℃≤T 14 ≤80℃;220℃≤T 21 ≤310℃,90℃≤T 22 ≤110℃,55℃≤T 23 ≤85℃,20℃≤T 24 ≤28℃,T 25 =31℃,230℃≤T 26 ≤280℃。 3. The heat recycling device according to claim 1, characterized in that: The heat measurement inlet of the first heat exchanger is connected to the output end of the compressor, and the heat measurement outlet of the first heat exchanger is connected to the heat measurement inlet of the second heat exchanger. The temperature is T 23 The carbon dioxide working medium is output from the heat outlet of the second heat exchanger; The cold side inlet of the first heat exchanger is connected to the outlet of the cold storage container through a first pipeline, the cold side outlet of the first heat exchanger is connected to the inlet of the first heat storage container through a second pipeline, the cold side inlet of the second heat exchanger is connected to the outlet of the cold storage container through a third pipeline, and the cold side outlet of the second heat exchanger is connected to the inlet of the second heat storage container through a fourth pipeline; The cold outlet of the third heat exchanger is connected to the input end of the turbine, the cold inlet of the third heat exchanger is connected to the cold outlet of the fourth heat exchanger, and the temperature is T 24 The liquid carbon dioxide working medium is input from the cold side inlet of the fourth heat exchanger; The heat measuring inlet of the third heat exchanger is connected to the outlet of the first heat storage container through a fifth pipeline, the heat measuring outlet of the third heat exchanger is connected to the heat measuring inlet of the fourth heat exchanger through a sixth pipeline, the heat measuring inlet of the fourth heat exchanger is also connected to the outlet of the second heat storage container through a seventh pipeline, and the heat measuring outlet of the fourth heat exchanger is connected to the inlet of the cold storage container through an eighth pipeline; Wherein, at least the first pipeline, the third pipeline, the fifth pipeline and the seventh pipeline are respectively connected with a flow control valve.

4. The heat recycling device according to claim 3, characterized in that: The fourth heat exchanger is also connected to an external heat source via a circulation pipeline, and the circulation pipeline is connected to the fourth heat exchanger at a position adjacent to a cold side outlet of the fourth heat exchanger.

5. The heat recycling device according to any one of claims 1 to 4, characterized in that: The heat exchange medium is heat transfer oil or water.

6. A carbon dioxide energy storage system, comprising a gas storage unit, an energy storage component, a liquid storage unit and an energy release component connected in a closed loop, characterized in that: The carbon dioxide energy storage system also includes a heat recycling device as described in any one of claims 1-5.

7. The carbon dioxide energy storage system according to claim 6, characterized in that: The energy storage component includes a low-pressure compressor and a high-pressure compressor, the first heat exchanger and the second heat exchanger are connected in series between the low-pressure compressor and the high-pressure compressor, the first heat exchanger is connected to the output end of the low-pressure compressor, the second heat exchanger is connected to the input end of the high-pressure compressor, and the input end of the low-pressure compressor is connected to the air storage unit.

8. The carbon dioxide energy storage system according to claim 7, characterized in that: The energy storage assembly further includes a condenser, and the output end of the high-pressure compressor is connected to the liquid storage unit through the condenser.

9. The carbon dioxide energy storage system according to any one of claims 6 to 8, characterized in that: The liquid storage unit is connected to the fourth heat exchanger via a liquid pump, and the liquid pump heats the liquid in the liquid storage unit at a temperature of T 24 The liquid carbon dioxide working medium is input into the fourth heat exchanger; the output end of the turbine is connected to the gas storage unit.

10. A control method for a carbon dioxide energy storage system according to any one of claims 6 to 9, characterized in that: The control method includes an energy storage stage and an energy release stage; wherein, During the energy storage phase: The gaseous carbon dioxide working medium in the gas storage unit is input into the compressor, and is compressed by the compressor to form the working medium at a temperature of T 21 The carbon dioxide working fluid is input into the first heat exchanger; Control the cold storage container to set the temperature to T 11 The heat exchange medium is input into the first heat exchanger, and the temperature is T 21 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 12 The heat exchange medium is input into the first heat storage container for storage and the temperature is obtained as T 22 The carbon dioxide working medium is input into the second heat exchanger; Control the cold storage container to set the temperature to T 11 The heat exchange medium is input into the second heat exchanger, and the temperature is T 22 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 13 The heat exchange medium is input into the second heat storage container for storage and the temperature is obtained as T 23 The output of carbon dioxide as working fluid; For the temperature T 23 The carbon dioxide working fluid is condensed and liquefied to obtain the temperature T 24 The liquid carbon dioxide working medium is input into the liquid storage unit; During the energy release phase: The temperature in the liquid storage unit is T 24 The liquid carbon dioxide working medium is input into the fourth heat exchanger; Control the second heat storage container to set the temperature to T 13 The heat exchange medium is input into the fourth heat exchanger, and the temperature is T 24 The liquid carbon dioxide working medium is heated and evaporated to obtain the temperature T 11 The heat exchange medium is input into the cold storage container for storage and the temperature is T 25 The carbon dioxide working medium is input into the third heat exchanger; Control the first heat storage container to set the temperature to T 12 The heat exchange medium is input into the third heat exchanger, and the temperature is T 25 The carbon dioxide working fluid is heat exchanged to obtain the temperature T 14 The heat exchange medium is input into the fourth heat exchanger and the temperature is T 26 The carbon dioxide working medium is input into the turbine; Wherein, the temperature is T 14 The temperature of the heat exchange medium output from the second heat storage container is T 13 After the heat exchange medium is combined, the temperature T 24 The liquid carbon dioxide working medium is heated and evaporated to form the temperature T 11 The heat exchange medium is input into the cold storage container for storage; the temperature is T 26 The carbon dioxide working medium is input into the gas storage unit after the temperature is reduced by the turbine doing work.

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